Device for simultaneously interlocking a plurality of actuators

ABSTRACT

The invention relates to a device ( 3 ) for simultaneously interlocking a plurality of actuators ( 1 ) by means of a first locking element ( 5 ) which is assigned to each final control element ( 2 ) of an actuator ( 1 ) and which interacts with a second locking element ( 6 ). The second locking element is fixed inside the housing ( 4 ) in an actuating direction of the final control element ( 2 ) and is displaced into an interlocking position by spring force and into an unlocking position by an assisting force. The invention provides that a plurality of second locking elements ( 6 ) are interconnected and are actuated by a common device ( 11 ). As a result, the variety of parts, the safety risk, the weight, and the constructional complexity are reduced which is very important especially when the inventive device is used in helicopter.

FIELD OF THE INVENTION

The invention concerns a device for the simultaneous locking of aplurality of actuators.

BACKGROUND OF THE INVENTION

In many cases of control technology, actuators are employed, which, upondropping out of operation or being switched off from the energy supply,are brought into a safety position and locked in that position. Gotte,H. J., in “Single Blade Control in a Helicopter by means ofServo-hydraulic Actuators in the Rotor Head”, 11th Achner FluidTechnology Colloquium, Field of Expertise, “Hydraulics”, in Aachen 1994,made known the provision of safety pistons in the case of helicopterswith actuators for individual control of rotor blades. These pistons,upon failure of energy for one actuator piston, are run back into a safeposition and held there. For this purpose, the safety pistons possess aconically shaped end, which engages itself in a wedge shaped annulargroove in the actuator piston. When the actuator is hydraulicallyactivated, the hydraulic pressure acts on the conical end of the safetypistons and slides these safety pistons against the force of a springinto a free float position for the actuator pistons. If the hydraulicpressure totally fails, then the springs slide the safety pistons backinto the wedge shaped groove and lock the control pistons in positionwithout play. The said springs can be gas springs.

A separate locking apparatus with an operating mechanism is provided foreach actuator. Upon failure of energy supply, all locking apparatusesmust be operated at the same time and all actuators must be locked. Thisis particularly necessary, if the actuators or the locking mechanismsare not hydraulic, but actuated by electricity. Because of themultiplicity of the necessary components, the safety risks are thusincreased along with construction expense and the weight.

SUMMARY OF THE INVENTION

The invention has the purpose of creating a device for the simultaneouslocking of a plurality of actuators, which is also suitable forapplication with either electrical or electromagnetic operatedactuators, as well as requiring relatively little energy andinstallation space. This purpose is achieved by the features of claim 1.Further embodiments arise from the subordinate claims.

In accord with the invention are several second locking elementsconnected to one another. These are operated by a common apparatus. Inaccord with the number of the locking elements so joined together, justso many operational parts are correspondingly dispensed with, so thatthe number of the necessary components is strongly reduced. Thereby, thesafety risk is minimized, which has great bearing on helicoptersoperation. Beyond this, the weight and the cost of construction islessened.

The connection of the second locking elements between one another isformulated very simply, if all locking elements are located in oneplane. These planes can be a longitudinal plane or a transverse plane,advantageously, the first locking elements and/or the actuators arelocated in one plane, so that, by means of transition elements to bridgeover, the distances due to different planes are avoided.

Particularly advantageous is the application of the invented device inthe case of helicopters. In this case, the safety risk, the weight andthe inertia in the rotating system play a significant role. Beyond this,for the individual control of the rotor blades, as a rule severalactuators are required in the rotating system. In the case of failure ofthe supply of energy, the said blades simultaneously must be broughtinto a safe position and locked, in order that the helicopter can bemore safely navigated by mechanical means. Advantageously, the actuatorsoperate by means of a mixing arm as part of the control system of therotor blades. The mixing arms are installed within the rotor-mast andpossess three interconnecting axles, namely, one for the actuator, onefor the control rods of the mechanical control and one for a control rodconnected to a pitch change horn.

The first locking elements are, in an advantageous manner, in the areaof the pivoted axle of the actuator on the mixing arm and are there toconnected. If the first locking element is locked by the second element,then the individual control of the rotor blades is blocked from theactuator. Under this condition, only the mechanical control isoperative. Now too, the first and second locking elements advantageouslyare placed in a plane of rotation of the rotor-mast, whereby the secondlocking element, can be connected with one another by means of a lockingring or a star-shaped element. The second elements, now being connectedtogether, in accordance with one embodiment can be constructed as wedgeshaped recesses of the locking ring, into which the first lockingelements can engage, upon displacement of the locking ring or the starshaped element. For unlocking, the locking ring or the star shapedelement is rotated by an auxiliary force countering the force of aspring into an unlocking position, into which the first locking element,at least within specified limits, is freely movable in the positionaldirection of the actuator. Upon shutting off, or by the failure ofenergy, the prestressed spring turns back the locking ring, or thealternate star-shaped element, into the locking position, so that thefirst locking element is locked in a more safe position. Instead of therotational movement of the locking ring or the start shaped element, itis also possible, that the locking ring, that is, the connection part ofthe second locking element carries out an axial movement leading to thelocking of the first locking element, if the locking elements arecorrespondingly constructed or placed for such a function.

Play and positional tolerances can lead to problems by the placement ofseveral actuators on one locking ring. These can, in a reliable manner,be compensated for, in that, either the first of the second lockingelements are made resilient in a springing manner and are themselvesprestressed. This has the result, that a clamp up is excluded on thepart of the locking and in the locked condition, some freedom of play isassured.

In the description and in the claims, many features in this connectionare presented and described. The expert will give consideration to thecombined features in the concept of the purpose to be achieved and cometo advantageous further combinations on his own.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described, by way of example, with referenceto the accompanying drawings in which:

FIG. 1 a schematic partial, longitudinal section through a rotor mast ofa helicopter,

FIG. 2 a development of a locking ring in the area II of FIG. 1,

FIG. 3 a section through the locking mechanism corresponding to the lineIII—III in FIG. 1,

FIG. 4 is a partial section of an embodiment of a locking element onsection line 4—4 of FIG. 5;

FIG. 5 a plan view of the embodiment of the locking element in FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

In a rotor mast 4 of a helicopter, which mast is turning about an axisof rotation 13 there are provided in one rotational plane and evenlyapportioned about the circumference, four mixing arms 7 with pivot axles8, 9, and 10. A piston rod 2, acting as a positioner for an actuator 1is connected with pivot axle 8, while on the pivot axle 10, at the otherend of the mixing arm 7, a mechanical control rod for the navigation ofthe helicopter is pivotally attached. This control rod is not furtherdescribed. The positioning signal of the actuator 1 and thus that of thesaid mechanical control rod are transmitted by means of a control rodconnected to an assigned rotor blade of the helicopter. This control rodis attached to the pivot axle 9 of the mixing arm 7.

An apparatus 3 for the simultaneous locking of the actuator 1 contains afirst locking element 5 and a second locking element 6. In the area ofthe pivot axle 8, the first locking element 5 is firmly bound to themixing arm 7. This first locking element 5 engages itself in the secondlocking element 6, which is affixed in a position direction 15 of theactuator 1 in the rotor mast. The second locking element 6 comprises awedge shaped recess 12 in a locking ring 11, into which said recess thefirst locking element 5 engages. Because of the wedge shape, the firstlocking element 5 is centered and at the end of its movement in thelocking direction, the two wedge shaped surfaces mutually fit withoutplay.

From the FIGS. 4 and 5, it may be seen, that the first locking element 5possesses a first wedge element 16 and a second wedge element 17. Thefirst wedge element 16, by means of the jaw 20, is coupled onto thepivot axle 8 relative to the positioning movement direction of thepiston rod 2 on the mixing arm 7. The second wedge element 17 can beslidingly displaced along a dove tailed guide 21 opposite to the firstwedge element 16.

Between the wedge elements 16 and 17, is placed a plate spring 18,which, by means of the screw 19 has been pre-stressed. If an actingforce from pressure on the plate spring 18 exceeds the given pre-stressproduced by the screw 19, for instance, upon a locking action, then theslidable second wedge element 17 approaches the stationary first wedgeelement 16. As a whole, this gives the prestressed wedge element 5 aresiliency when the said prestressed force is overcome.

In the locked condition, the play and position tolerances between thefirst and second locking elements 5 and 6 are compensated for by thedescribed spring arrangement. By means of this arrangement, even indifferent engagement positions, a complete locking of all actuators isassured. The same effect can be attained, if, instead of the first wedgeelement 5, the second element 6 is designed to be springingly resilient.

The locking ring 11 can be rotated through a limited angle 14 ofrotation. For the unlocking of the actuator 1, the ring, by means of anauxiliary force opposing the force of a spring, is brought into anunlocking position, in which, the first locking element 5 can freelymove itself, at least in a limited distance, in the positioningdirection 15 of the actuator 1. If the energy supply is shut off, orfails, then the locking ring 11, by means of the spring force is broughtback into the locking position, in which the first locking element 5lies free on the sides of the wedge shaped recess 12, and thus with thepiston rod 2, which is coupled thereto, is blocked in the positioningdirection.

Reference Numbers and Items

1 Actuator

2 Piston rod

3 Complete apparatus within motor mast (FIG. 1)

4 Rotor mast

5 First blocking element

6 Second blocking element

7 Mixing arm

8 Pivot axle, connecting 7 to 2

9 Pivot axle, connecting 7 to control rod(s)

10 Pivot axle, pivot for 7, remote from 8

11 Locking ring

12 Recess, V-shape, receives 6

13 Axis of rotation of rotor mast

14 Direction of rotation of 11, limited

15 Axial displacement of piston rod

16 First wedge element

17 Second wedge element

18 Plate spring between 16, 17

19 Screw, stresses 18

20 Jaw, FIG. 4

21 Dove tailed guide block, responds to 18

Claimed is:
 1. A device (3) for the simultaneous locking of a pluralityof actuators (1) with a first locking element (5) for each positioningcontrol piston rod (2) of an actuator (1), which locking element (5)coacts with a second locking element (6), the second locking element (6)being fixed in the position direction (15) of the piston rod (2) in ahousing (4), and the first locking element (5) further, by means ofspring force, can be displaced into a locking position and through anauxiliary force into an unlocking position, whereby a plurality ofsecond locking elements (6) are bound to one another and are operated bya common apparatus (11), wherein the actuators (1) are located in arotating system of a helicopter in which they serve the purpose ofindividually controlling the rotor blades of said helicopter and thesecond locking element (6) are formed, by means of one of V-shapedrecesses in a locking ring (11) and in a star shaped element, into whichthe first locking elements (5) engage, upon the displacement of one ofthe locking ring (11) and of the star shaped element.
 2. The device (3)according to claim 1, wherein the actuators (1) operate the controlsystem of the rotor blades by means of a mixing arm (7).
 3. The device(3) according to claim 1, wherein the first locking elements (5) in thearea of the pivot axle (8) of the actuator (1) on the mixing arm (7) arefast with said mixing arm (7).
 4. The device (3) according to claim 3,wherein all locking elements (5, 6) lie in one plane and that this planeof rotation.
 5. The device (3) according to claim 1, wherein theunlocking position and the locking position is achieved by the rotationof one of the locking ring (11) and the star shaped element.
 6. Thedevice (3) according to claim 1, wherein the unlocking and the lockingposition is attained by an axial displacement of one of the locking ring(11) and the star shaped element.
 7. The device (3) according to claim1, wherein the first or the second locking elements (5, 6) are designedto be springlike resilient and are of themselves prestressed, in orderto compensate for play and positional tolerances of the locking elementsupon locking.
 8. The device (3) according to claim 7, wherein the firstlocking element (5) possesses a first coupled wedge element (16) on themixing arm (7) and a second wedge element (17) which is slidablerelative to the first coupled wedge element (16) against the force of aprestressed plate spring (18).